The objectives of UCSD Pediatric ACTU are to identify promising new treatments for persons infected with HIV and to bring these agents as expeditiously as possible to clinical trials within the ACTG with the goal of improving treatments for HIV infection and its associated infections, and preventing maternal-infant transmission. The UCSD Pediatric ACTU is an integrated program which from its inception has incorporated core laboratory support and developmental laboratory research with clinical investigation. The clinical and laboratory cores of Neuropsychology Retrovirology (9001) will continue to provide protocol required core clinical and laboratory support for ACTG-sponsored clinical studies. Additionally, several developmental programs will enhance our ability to advance the treatment of pregnant women and children infected with HIV. These include: (1) A Developmental Retrovirology Program (0002) that will develop dependable, standardized and biologically meaningful assays of virus replication to assess disease risk and effective interventions. (2) A Developmental Immunology Program (0003) that addresses the need for immunological disease markers in children by measuring cytokine expression and cell proliferation in immune cells and by correlating these parameters with HIV expression and cell proliferation in immune cells. The UCSD Pediatric ACTU has already established an integrated program of core clinical research, core laboratory support and developmental research. We have developed a diverse and cohesive program which draws upon the expertise and excellence of clinical investigators, core laboratory support and developmental research. The participation of each of these components of our program will contribute to the continued success of our ACTU.